20021851867 has 2 divisors, whose sum is σ = 20021851868. Its totient is φ = 20021851866.

The previous prime is 20021851849. The next prime is 20021851907. The reversal of 20021851867 is 76815812002.

It is an a-pointer prime, because the next prime (20021851907) can be obtained adding 20021851867 to its sum of digits (40).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20021851867 - 2¹⁵ = 20021819099 is a prime.

It is not a weakly prime, because it can be changed into another prime (20021851067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010925933 + 10010925934.

It is an arithmetic number, because the mean of its divisors is an integer number (10010925934).

Almost surely, 2^20021851867 is an apocalyptic number.

20021851867 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021851867 is an equidigital number, since it uses as much as digits as its factorization.

20021851867 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 53760, while the sum is 40.

The spelling of 20021851867 in words is "twenty billion, twenty-one million, eight hundred fifty-one thousand, eight hundred sixty-seven".